Uterine Inversion

1. What every clinician should know

Clinical features and incidence

Uterine inversion is when all or part of the uterus has invaginated into the endometrial cavity and possibly into the vagina. In some series the uterine inversion is further stratified by (1) extent: incomplete (no part of corpus past cervix), complete (inversion extends into the vagina), and prolapsed (protrudes past the introitus; and (2) duration: acute (prior to cervical contraction), subacute (after cervical contraction), and chronic (present for more than 4 weeks). It can occur with vaginal or cesarean delivery.

Acute uterine inversion in the third stage of labor is an obstetric emergency that may cause profound hemorrhage. When a patient has brisk bleeding and a mass is felt in the vagina and the uterine fundus cannot be palpated, uterine inversion should be suspected. The reported incidence in the United States is 1:1200-1:5900; institutions in Europe report an even lower rate.

Risk factors

Risk factors that have been reported include macrosomia, short cord, primiparity, fundal placentation and abnormal placental attachment.

2. Diagnosis and differential diagnosis

A. Establishing the diagnosis

In complete uterine inversion the uterus is turned inside out and it typically presents as a red mass protruding into the vagina or through the introitus. Patients may report persistent abdominal pain or lower abdominal pressure. The placenta may still be attached. The differential for postpartum vaginal mass would also include prolapsing myoma.

Incomplete or partial inversion may be more subtle, but should be suspected with persistent postpartum hemorrhage and a fundus that cannot be palpated. The majority of the literature on this topic describes the diagnosis as being made clinically; however, case reports suggest that ultrasound may be useful in cases of diagnostic uncertainty.

B. Differential diagnosis

The other possible etiology of a mass in the vagina would be prolapsed myoma or polyp. The differential diagnosis for postpartum hemorrhage is more extensive and would include uterine atony, cervical or vaginal laceration, uterine rupture, placenta accreta or bleeding diathesis due to coagulation disorder.

3. Management

The two cornerstones of mangement are (1) replacement of the uterus and (2) resuscitation from the hemorrhage.

Discontinue uterotonic therapy.

Notify the anesthesia team so that adequate pain relief can be achieved and preparations can be made should general anesthesia or operative intervention be required.

Prepare for large hemorrhage by (1) establishing two sites of IV access, at least one of which should be large bore, and (2) ordering blood products and laboratory studies (hemoglobin, platelet count, coagulation indices).

Replacement of the uterus should be attempted immediately, as it is most easily achieved before the cervix and lower uterine segment begin to contract.

Administer uterine relaxants. Start with what is immediately available, such as terbutaline (0.25mg subcutaneously), nitroglycerin (50-500 micrograms intravenously) or magnesium sulfate (2-6 grams intravenously over 15 minutes). If these are unsuccessful then halogenated anesthetics (halothane, enflurane, etc) can be utilized.

Apply steady pressure to the uterus to push it back through the vagina and cervix. Generally the portion that inverted last, closest to the cervix, should be replaced first and the uterine fundus replaced last.

If the placenta is still attached, removal should not be attempted until the uterus has been restored to its appropriate position.

In refractory cases laparotomy is the next step. Methods that have been described to correct the inversion surgically include: (1) serial clamping and upward traction on the round ligaments to elevate the fundus (Huntington procedure); and (2) vertical incision along the posterior wall of the uterus in the area of the constriction and then manual repositioning of the fundus (Haultain procedure).

Once the uterus is repositioned:

Palpate for evidence of uterine rupture and maintain a hand within the cavity until the uterus feels contracted.

Initiate oxytocin or alternate uterotonic such as methylergonovine or carboprost to improve uterine tone in order to decrease the risk for recurrent inversion and minimize further blood loss.

Insert Foley catheter to monitor urine output given large blood loss.

The utility of antibiotics in preventing infectious morbidity is not well established, so use should be for reserved for women with other obstetric indicaitons for antibiotic use.

Transfusion of blood products should be based upon typical clinical considerations.

4. Complications

Complications due to condition

The primary complication is hemorrhage and its attendant risks (shock, multi-organ damage, Sheehan syndrome, need for hysterectomy). The risk for requiring a blood transfusion is nearly 50% in some series. Left untreated, the condition can result in persistent blood loss and tissue necrosis.

Complications due to management

The risks faced by the patient during treatment of uterine inversion include those risks associated with general anesthesia and with transfusion of blood products.

5. Prognosis and outcome

Acute cases can result in hemorrhagic shock and its attendant sequelae as described above. If the problem is immediately managed, few long-term sequelae have been described.

The risk for recurrence in a future pregnancy is not known. However, there are case reports of uncomplicated subsequent pregnancies.

6. What is the evidence for specific management and treatment recommendations

(Retrospective review of 56 cases of uterine inversion, the largest contemporary series identified. Some combination of terbutaline, magnesium sulfate or various anesthetic agents were required in 36 of the cases; no cases required laparotomy for repositioning.)

(Second largest series identified. Found a reduction in the indicence of uterine inversion in recent years, which the author speculated was due to active management of the third stage of labor. Twenty subjects went on to have an additional 26 deliveries, with no cases of recurrence.)

(An earlier series of six cases of uterine inversion that described the use of tocolytic agents [magnesium sulfate and terbutaline sulfate] to relax the uterus, allowing general anethesia to be avoided.)